Manufacture of rubber goods from rubber dispersions



Dwz, 1930.

MANUFAGTURE P. K LEIN ET AL 1,783,435

OF RUBBER GOODS FROM RUBBER DISPERSIONS Filed April 15, 1927 /7 f lhPatented Dec. 2, 1936 UNITED A sfrfrrfi'sv PATENT. oF-Flcr.

age-UL xnrum'or BUDAPEST, HUNGARLAND ANDREW. szEevARI, or AxRoNgzoHIo,AssrGNoRs 'ro AMERICAN ANonEr-Nc., or AKRON, omo, A CORPORATION or DELA-MANUFAGTURE or RUBBER eoons FROM RUBBER nrsrnnsrons Application filed-April 13, 1927, Serial iNo. 183,606, and `in` Hungary and Germany April14, 1926. .I

In the manufacture of 'rubber .goods by electrophoretic precipitating ofrubber from` rubber dispersions on the anode, or on a precipitatingbacking or support 'surrounding the anode," gases are liberated at ltheCathode dwing to the electrolysis which takes place simultaneously withthe cataphoresis. The gas bubbles escaping from the cathode may reachthe rubber precipitate and adhere to it, there- '10 by impairing theuniformity of the rubber coating. Although it is ,possible to preventthe gases liberated at the cathode from reaching the rubber precipitateby inserting delecting walls or diaphragms lbetween the cathode and theprecipitating backing, this method may be unsuitable, or evenimpracticable under certain conditions, especially in the manufacture ofclosed hollow articles such as inner tubes of tires.

-According to this invention in thecataphoretic device means areprovided to pre` vent the liberation of gas atthe cathode duringcataphoresis. ing lat the cathode may be used suppressing the generationof hydrogen. Forl this purpose oxidizing depolarizing agents may be v'used.

example, lead peroxide. AThe hydrogen ions cathode is used, the surfaceof which consists of a metal oxide, which is'easilyireduced, for

discharging at the cathode reducethis oxide surface. Preferably'thecathode consists of lead, the surface of which has been converted tolead peroxide, for example, by means of the well known storage batteryprocess.-

.l1-b, preferably having a removable lining,

for example, of'zinc. The two halves-11a For example means act-According to this invention, preferably a and 11b, of the mold aredetachably joined in any suitable manner, for example, by bolts 17. l isthe annulancathode Within the mold which is interrupted at 19 and has ashaft 7 to attach the cathode to the mold. The cathi vode consistspreferably of an iron tube with 'an outer coating of lead. The layer oflead is formed in the well known manner, which is used for storagebattery plates so that a porouslayer of-lead peroxideis generated on itssurface. In order to prevent the crumbling of this surface coating, thecathode can ,be covered with a protective coating of any materialpermeable or semi-permeable to'liqnids, for example, a coating ofgelatin. The tubular cathode is preferably provided with an opening '16diametrically'opposite to the shaft 7, or with a plurality of openings.The shaft 7 of the cathode isV inserted in the mold andsealedwater-tight by means of a stuffing 'box 8 having an insulatinglining. Itcan be firmly' attached-to the carrier 5 by meansY of anysuitable device, for example, the threaded box 4 havinginsulatinglinings 2 and 6. The carrier 5 Ais rigidly 'connected to theone part 11b of the mold in an exactly .centered posi- When the mold hasbeen put together as' described'abovq and is in the horizontalposition,"it is filled through the tubular cathode 1 with therubberdispersion. This rubber dispersion enters the mold through the opening16, and the air escapes from the mold throigh the tube 9. When thehollow of the mold islled with rubber dispersion up to 'the lvel'of themouth of the tube 9, the tube l is attached by the terminal 3 to thenegative pole of a source of current, and the mold l1 is attached byterminal 2() to the positive vpole so that the rubber is precipitated onthe inner wall of mold l1. The liquid canalso circulate continuously.through the mold during the cataplioresis and'escape at 9, but it ispreferable to check the circulation so that only the necessary amount ofow is maintained to permit formation of a uniform precipitate.

lBy suitable choice of the metal of the inner wall of the mold 11, forexample by use of zinc, and by suitable composition ofthe rubberdispersion, formation of gas at the anode can be prevented in the-wellknown manner. It will be understood that the electrophoreticprecipitation must be conducted as known per se in sueha way that no gasis developed on the precipitation surfaces.Y For this purpose insteadof'using metallic precipitating molds, a porous non-conducting Waterpermeable depositing mold can be used, for example, in the mannerdescribed in Patent No.

1,548,689. This non-conducting mold can be connected to theelectroconductive anode by a layer of electrolyte, either free orabsorbed in a non-liquid material. The hydrogen ions discharging atthe'cathode 1 are combined with the lead peroxide layer on the cathodeso that no gases are set free in the hollow -of the mold.

When a relatively thick precipitate has been formed, the flow ofrubbersolution through the tube 1 is stopped, and the mold is rotated onthe pivot 13 to an angle of about 180O in the direction of the arrow 21vinto the position indicated by chain lines. AIn this way the stuffingbox 8 withthe tube 9 is turned downwards. The liquid is then drainedfrom the mold up to a residue of a few drops. The

tube 1 can then be connected to a, hot air conduit so that the hot airenters through the opening 16 of the cathode and escapes through tube 9,thus circulating through the mold and drying the precipitated rubber.The mold is then opened. vAfter loosening the threaded box 4, the shaft7 is disconnected from the l cathode, and the elastic hollow tube formedby precipitated rubber can be removed from the mold together with thecathode in its interior. The elastic annular tube can be stripped offfrom the cathode owing to the interruption 19 of the ring forming thecathode. The tube made in this manner can be cured in the usual way.'Ihe term, rubber dispersion,7 includes all natural or articial,vulcanized or uri/vulcanized dispersions of Irubber, gutta percha,balata, and the like a cathode immersed in the aqueous dispersion andcapable of inhibiting escape of gas at the cathode, whereby gasesnormally liberated at the'cathod'e are prevented from entrainment withthe deposited rubber layer.

2. The process for the manufacture of hollow rubber goods from aqueousdispersions of rubber by elect-rodeposition of rubber with anexteriormold-formed surface which comprises lconfining a body of theaqueous dispersion in a closed container constituting the anode,preparing a cathode by associating with it a depolarizer,electrodepositing a `rubber layer from an aqueous rubber dispersionutilizing said prepared cathode immersed in the dispersion whereby gasesnormally liberated at the cathode are reduced by said'depolarizer andinhibited from'entrainment with the deposited rubber layer.

3. The process for the manufacture of hollow rubber goods from aqueousdispersionsv of rubber by electrodeposition of rub ber which comprisescon'fining'a body of the aqueous dispersion in a closed containerconstituting the anode, electrodepositing a rubber layer from an aqueousrubber dispersion utilizing a lead peroxide-coated cathode immersed insuch dispersion, whereby gases normally liberated at the cathode reactwith the lead peroxide and are inhibited from entrainment with thedeposited rubber layer.

4. The process for the manufacture of hollow rubber goods from aqueousdispersions of rubber by electrodeposition of rubber with an exteriorvmold-formed surface which comprises confining a body of aqueousdispersion in a closed container constituting an anodic surface of anelectric cell, depositing by an electric current traversing saiddispersion .through the intermediary of a cathode immersed therein alayer of rubber upon said surface, and reducing the gases formed at thecathode to inhibit the entrainment of gases in the rubber layerdeposited.

5. The steps in the process of making hollow rubber articles byelectrodeposition from aqueous rubber dispersions with an exteriormold-formed surfacewhich comprises conlining a quantity of aqueousdispersion in contact with surface capable of producing the exteriorcontour of the hollow article, depositing by an electric currenttraversing the said dispersion through the intermediary of a cathodeimmersed therein a layer of rubber upon said surface, and oxidizing thegases formed at the .cathode to inhibit their entrainment in the rubberlayer deposited, whereby gases normally liberated at the cathode arereacted with said agent and inhibited from entrainment with thedeposited rubber layer.

6. Apparatus for the manufacture of hollow articles comprising a moldadapted to contain an aqueous dispersion of rubber, and having aninterior anodic surface upon contain an aqueous dispersion of rubber,and l which a layer of rubber is adapted-to be deposited byelectrophoresis, a cathode disposed within said mold, and meansassociated with the .cathode for preventing the liberation of gasesformed at the' cathode, whereby gases normally-liberated at the cathodeare inhibited from entrainment with the deposited rubber layer.

7. Apparatus for the manufacture lof hollou'T larticles comprising amold adapted-to having an interior anodic surface upon which a layer ofrubber is adapted to be deposited by electrophoresis, and a lead cathodedisposed within said mold having a surface coating of lead peroxide,whereby gases normally liberatedat the cathode are reacted with saidagent and inhibited from entrainment with the deposited rubber layer.

8. Apparatus for the manufacture of hollow articles by electrophoresiscomprising a sectional mold having a small'duct commuy. nicating withthe outside when sections are closed, and a hollow cathode disposedwithin said mold and provided' with means for the passage of aqueousdispersion of material to be deposited therefrom into the mold, wherebysaid dispersion can be supplied to and distributed in said mold prior toand during the electrophoretic action.

' 9. Apparatus .for the manufacture of hollow articles byelectrophoresis comprising a sctional mold having a small Vopening whensections are closed, and a hollow cathode substantially centrallydisposed within said mold when its sections are united and proividedwith means for uniformly distributing' a'fiuid in and through the mold,whereby said dispersion can b e supplied to and distributed in said moldprior to'and during the electrophoretic action.

10. Apparatus for the manufacture of hollow annular articles byelectrophoresis comprising an annular sectional mold comprising ananode, and an annular cathode disposed within the mold, and insulatedtherefrom and means associated with the mold and the cathode forcirculating the material to be deposited through the mold@ ll. Apparatusfor themanufacture of hollow annular articles by electrophoresiscomprising an annular sectional mold comprising an anode, and an annularcathode disposed within the moldl and insulated therefrom, and meansassociated with the cathode forinhibiting the liberation of gases formedat the cathode.

In testimony whereof we affix our signatures. v

PAUL KLEIN. ANDREW SZEGVARI.

